@@ -1005,7 +1005,12 @@ static int powerpc_smt_flags(void)
*/
static int powerpc_shared_cache_flags(void)
{
- return SD_SHARE_PKG_RESOURCES;
+ return SD_SHARE_PKG_RESOURCES | asym_pack_flag;
+}
+
+static int powerpc_shared_proc_flags(void)
+{
+ return asym_pack_flag;
}
/*
@@ -1044,8 +1049,8 @@ static struct sched_domain_topology_level powerpc_topology[] = {
{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
#endif
{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
- { cpu_mc_mask, SD_INIT_NAME(MC) },
- { cpu_cpu_mask, SD_INIT_NAME(DIE) },
+ { cpu_mc_mask, powerpc_shared_proc_flags, SD_INIT_NAME(MC) },
+ { cpu_cpu_mask, powerpc_shared_proc_flags, SD_INIT_NAME(DIE) },
{ NULL, },
};
@@ -1671,7 +1676,9 @@ static void __init fixup_topology(void)
{
int i;
- if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
+ if (is_shared_processor()) {
+ asym_pack_flag = SD_ASYM_PACKING;
+ } else if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
asym_pack_flag = SD_ASYM_PACKING;
}
If there are shared processor lpars, underlying Hypervisor can have more virtual cores to handle that actual physical cores. Starting with Power 9, a core has 2 nearly independent thread groups. On a shared processors lpars, it helps to pack threads to lesser number of cores so that the overall system performance and utilization improves. PowerVM schedules at a core level. Hence packing to fewer cores helps. For example: Lets says there are two 8-core Shared lpars that are actually sharing a 8 Core shared physical pool, each running 8 threads each. Then Consolidating 8 threads to 4 cores on each lpar would help them to perform better. To achieve this, enable SD_ASYM_PACKING flag at CACHE, MC and DIE level. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- arch/powerpc/kernel/smp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)